Class A airspace on WAC charts Bahamas and Cuba


#1

I noticed that WAC chart CH-25 has a box just east of Bimini (MYBS) that says

CTA/FIR NASSAU
MYNN
6000/1200 CTA CLASS E
6000/SFC FIR CLASS A.

I know what FIR means, but what is a CLASS A FIR? It’s apparently different than ICAO Class A controlled airspace.